Free soil volume calculator: enter bed size and depth to get soil volume in cubic feet, cubic yards, litres, bags needed, and weight.
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Enter the inside length and width of your bed in feet, the soil depth in inches, and how many identical beds you are filling. Pick your soil type, which sets the weight per cubic foot, your bag size, and the extra percentage for settling, which defaults to 10 percent. Base volume is length multiplied by width multiplied by depth in feet, multiplied by bed count. The volume to order multiplies that base by one plus the settling percentage, because fresh soil settles 10 to 15 percent in the first weeks, and more for compost-rich mixes. Cubic yards divide cubic feet by 27, litres multiply cubic feet by 28.3168, cubic metres multiply by 0.0283168, bags round the adjusted volume up to whole bags, and weight multiplies adjusted volume by the soil density.
A rectangular bed's volume is length multiplied by width multiplied by depth, with depth converted from inches to feet by dividing by 12. A 4 foot by 8 foot bed at 12 inches deep holds 4 times 8 times 1, or 32 cubic feet, which is 32 divided by 27, or 1.19 cubic yards. With the default 10 percent settling extra, the volume to order is 35.2 cubic feet, or 1.30 cubic yards, which needs 18 bags of 2 cubic feet each, rounded up, and weighs about 2,640 pounds as topsoil at 75 pounds per cubic foot. The shortcut many gardeners use is cubic yards equals square feet multiplied by depth in inches divided by 324, which gives the same answer: 32 square feet times 12 divided by 324 equals 1.19 cubic yards.
Step 1: measure the inside of the bed, not the outside, because thick timber walls can steal an inch or more on each side. Step 2: enter length, width, and depth, and the number of identical beds, rather than adding beds together by hand. Step 3: pick your soil type and bag size, and keep the 10 percent settling extra unless you are topping up an established bed that has already settled. Step 4: order by the volume to order figures, and check the weight before loading a trailer, because a cubic yard of topsoil weighs roughly 2,200 pounds and most small trailers safely carry only about one cubic yard. If you already have soil in the bed, order only the gap: measure the depth still needed, not the full bed depth.
A 4x8 raised bed needs 16 cubic feet at 6 inches, 32 at 12 inches, 48 at 18 inches, and 64 at 24 inches, before settling extra, which translates to 0.59, 1.19, 1.78, and 2.37 cubic yards. In 2 cubic foot bags, those depths need 8, 16, 24, and 32 bags before settling, or 9, 18, 27, and 36 bags with 10 percent extra rounded up. A new lawn at 4 inches over 1,000 square feet needs about 12.35 cubic yards, or about 13.6 with 10 percent extra. A border bed 6 metres by 1 metre at 20 centimetres needs about 1.32 cubic metres, or about 1,850 kilograms of standard topsoil. One cubic yard covers 324 square feet at 1 inch, 162 at 2 inches, 81 at 4 inches, 54 at 6 inches, and 27 at 12 inches, which is a handy check for any lawn or levelling job.
New lawns from seed need 4 to 6 inches of topsoil, turf or sod needs 3 to 4 inches, and lawn levelling should be spread only 1 to 2 centimetres per pass. Flower beds need 6 to 8 inches, vegetable beds 8 to 12 inches, and raised beds their full height, with 6 inches suiting greens and herbs, 12 inches suiting most vegetables, and 18 to 24 inches suiting root crops, potatoes, and tall tomatoes. Trees need 18 to 24 inches in the planting pit, wider than deep. Lawns for levelling, in metric terms, need 10 to 15 centimetres for a new lawn and 25 to 30 centimetres for a vegetable bed, so the same depth guide works in either unit system if you convert before ordering.
Topsoil weighs about 75 pounds per cubic foot, or about 2,200 pounds per cubic yard, garden soil is similar, compost is lighter at about 40 pounds per cubic foot or 1,000 pounds per cubic yard, and potting mix is lightest at about 30 pounds per cubic foot or 600 pounds per cubic yard. Wet soil weighs 20 to 30 percent more than dry soil, so never overload a trailer with wet topsoil. A classic raised bed mix is 60 percent topsoil, 30 percent compost, and 10 percent perlite or vermiculite, which for a 4x8 bed at 12 inches with settling extra means roughly 0.78 cubic yards of topsoil, 0.39 of compost, and 0.13 of perlite. Mel's Mix, the square foot gardening recipe, is equal thirds compost, peat moss, and vermiculite, and it compresses 20 to 30 percent over a first season, so it needs the full settling allowance.
This soil mix ratio, 60 percent topsoil, 30 percent compost, and 10 percent perlite, is a reliable starting point that you can adjust for drainage or fertility.
Bagged soil costs roughly 4 to 8 dollars per cubic foot, while bulk soil costs roughly 25 to 50 dollars per cubic yard, or about 1 to 2 dollars per cubic foot, so bulk wins once you need about 1 cubic yard or more, before delivery fees of roughly 50 to 150 dollars. Bags per cubic yard are 36 for a 0.75 cubic foot bag, 18 for a 1.5 cubic foot bag, and about 19 for a 40 litre bag per cubic yard, or 25 per cubic metre. This calculator handles rectangular beds; for a round bed, use pi divided by 4 multiplied by diameter squared multiplied by depth, and for an L-shaped bed, split it into two rectangles and add them, which is the same method the dedicated shape calculators use. Never put a gravel layer at the bottom of a raised bed to save soil: it creates a perched water table, while logs and branches in a Hugelkultur layer break down usefully instead.
To estimate soil cost, multiply your volume to order by the price per cubic yard or per bag, and compare bagged and bulk prices on that same per cubic yard basis. For a circle bed, use the round bed formula given above, and for scale, 1000 square feet at 4 inches needs about 12.35 cubic yards before settling extra.
The most common mistakes are measuring the outside of the bed, mixing up cubic yards with square yards, entering 6 feet when you mean 6 inches, ordering the exact volume with no settling allowance, and ordering the full bed depth when soil is already present. Other mistakes include ordering by volume when the supplier quotes by weight, or the reverse, buying cheap unscreened soil for a fine lawn or seed bed, and using subsoil or fill dirt where topsoil is needed. Spread lawn levelling soil thinly, check your trailer or delivery access for a cubic yard of weight, and keep the order slightly generous: a bag or two left over is far cheaper than a second delivery fee.
At 12 inches deep, a 4x8 bed needs 32 cubic feet, or 1.19 cubic yards, before settling, and about 35.2 cubic feet, or 18 bags of 2 cubic feet, with the default 10 percent settling extra. At 6 inches it needs half that, and at 18 inches it needs half as much again.
Multiply length by width by depth in feet, then divide cubic feet by 27 for cubic yards. A 3 metre by 1 metre bed at 30 centimetres needs 0.9 cubic metres, or about 1,200 kilograms of topsoil, before settling extra.
Six inches suits greens and herbs, 12 inches suits most vegetables, and 18 to 24 inches suits root crops, potatoes, and tall tomatoes. For a new lawn, use 4 to 6 inches of topsoil, and for flower beds, 6 to 8 inches.
Four to 6 inches for a lawn from seed, and 3 to 4 inches under turf or sod. For levelling an existing lawn, spread only 1 to 2 centimetres per pass so grass is not smothered.
About 2,200 pounds dry, or up to about 2,700 pounds when wet, at roughly 75 pounds per cubic foot. Compost is lighter at about 1,000 pounds per cubic yard, and potting mix lightest at about 600 pounds.
About 36 bags of 0.75 cubic feet, 18 bags of 1.5 cubic feet, or 13 to 14 bags of 2 cubic feet, depending on rounding. In metric terms, a cubic metre holds 25 bags of 40 litres or 20 bags of 50 litres.
Topsoil is the upper layer of soil as dug, screened or unscreened, while garden soil is usually a blended mix of topsoil with compost or other organic matter, ready for planting. Garden soil suits beds directly, while plain topsoil often benefits from added compost.
Yes, for beds and borders garden soil usually works better than plain topsoil, because it already contains organic matter. For a new lawn, screened topsoil is the usual choice, topped with seed or turf.
You can, but it compacts and drains less well than a mix, so most gardeners blend topsoil with compost and perlite or vermiculite, typically 60 percent topsoil, 30 percent compost, and 10 percent perlite, for better structure and fertility.
Yes: top up settled beds with fresh compost and mix it through, rather than replacing all the soil. Remove any diseased plants and roots first, and refresh at least the top few inches each season.
Yes, buy 10 to 15 percent extra, because fresh soil settles in the first weeks, and compost-rich mixes can settle 20 to 30 percent over a season. This calculator adds 10 percent by default, and you can raise it for loose mixes.
Bulk is cheaper once you need about 1 cubic yard or more, at roughly 1 to 2 dollars per cubic foot versus 4 to 8 dollars bagged, before delivery fees of roughly 50 to 150 dollars. Below about a cubic yard, bags avoid delivery fees and waste.
It is exact for rectangular beds from the dimensions you enter, but real beds vary: inside measurements, uneven depth, and soil compaction all shift the true volume. The settling extra and whole-bag rounding cover most of that variation, so treat the result as an order quantity, not a laboratory measurement.